drivers/i2c/soft_i2c.c

   1 /*
   2  * (C) Copyright 2009
   3  * Heiko Schocher, DENX Software Engineering, hs@denx.de.
   4  * Changes for multibus/multiadapter I2C support.
   5  *
   6  * (C) Copyright 2001, 2002
   7  * Wolfgang Denk, DENX Software Engineering, wd@denx.de.
   8  *
   9  * SPDX-License-Identifier:     GPL-2.0+
  10  *
  11  * This has been changed substantially by Gerald Van Baren, Custom IDEAS,
  12  * vanbaren@cideas.com.  It was heavily influenced by LiMon, written by
  13  * Neil Russell.
  14  *
  15  * NOTE: This driver should be converted to driver model before June 2017.
  16  * Please see doc/driver-model/i2c-howto.txt for instructions.
  17  */
  18
  19 #include <common.h>
  20 #if defined(CONFIG_AT91FAMILY)
  21 #include <asm/io.h>
  22 #include <asm/arch/hardware.h>
  23 #include <asm/arch/at91_pio.h>
  24 #ifdef CONFIG_ATMEL_LEGACY
  25 #include <asm/arch/gpio.h>
  26 #endif
  27 #endif
  28 #if defined(CONFIG_8xx)
  29 #include <asm/io.h>
  30 #endif
  31 #include <i2c.h>
  32
  33 #if defined(CONFIG_SOFT_I2C_GPIO_SCL)
  34 # include <asm/gpio.h>
  35
  36 # ifndef I2C_GPIO_SYNC
  37 #  define I2C_GPIO_SYNC
  38 # endif
  39
  40 # ifndef I2C_INIT
  41 #  define I2C_INIT \
  42         do { \
  43                 gpio_request(CONFIG_SOFT_I2C_GPIO_SCL, "soft_i2c"); \
  44                 gpio_request(CONFIG_SOFT_I2C_GPIO_SDA, "soft_i2c"); \
  45         } while (0)
  46 # endif
  47
  48 # ifndef I2C_ACTIVE
  49 #  define I2C_ACTIVE do { } while (0)
  50 # endif
  51
  52 # ifndef I2C_TRISTATE
  53 #  define I2C_TRISTATE do { } while (0)
  54 # endif
  55
  56 # ifndef I2C_READ
  57 #  define I2C_READ gpio_get_value(CONFIG_SOFT_I2C_GPIO_SDA)
  58 # endif
  59
  60 # ifndef I2C_SDA
  61 #  define I2C_SDA(bit) \
  62         do { \
  63                 if (bit) \
  64                         gpio_direction_input(CONFIG_SOFT_I2C_GPIO_SDA); \
  65                 else \
  66                         gpio_direction_output(CONFIG_SOFT_I2C_GPIO_SDA, 0); \
  67                 I2C_GPIO_SYNC; \
  68         } while (0)
  69 # endif
  70
  71 # ifndef I2C_SCL
  72 #  define I2C_SCL(bit) \
  73         do { \
  74                 gpio_direction_output(CONFIG_SOFT_I2C_GPIO_SCL, bit); \
  75                 I2C_GPIO_SYNC; \
  76         } while (0)
  77 # endif
  78
  79 # ifndef I2C_DELAY
  80 #  define I2C_DELAY udelay(5)   /* 1/4 I2C clock duration */
  81 # endif
  82
  83 #endif
  84
  85 /* #define      DEBUG_I2C       */
  86
  87 DECLARE_GLOBAL_DATA_PTR;
  88
  89 #ifndef I2C_SOFT_DECLARATIONS
  90 #  define I2C_SOFT_DECLARATIONS
  91 #endif
  92
  93 #if !defined(CONFIG_SYS_I2C_SOFT_SPEED)
  94 #define CONFIG_SYS_I2C_SOFT_SPEED CONFIG_SYS_I2C_SPEED
  95 #endif
  96 #if !defined(CONFIG_SYS_I2C_SOFT_SLAVE)
  97 #define CONFIG_SYS_I2C_SOFT_SLAVE CONFIG_SYS_I2C_SLAVE
  98 #endif
  99
 100 /*-----------------------------------------------------------------------
 101  * Definitions
 102  */
 103 #define RETRIES         0
 104
 105 #define I2C_ACK         0               /* PD_SDA level to ack a byte */
 106 #define I2C_NOACK       1               /* PD_SDA level to noack a byte */
 107
 108
 109 #ifdef DEBUG_I2C
 110 #define PRINTD(fmt,args...)     do {    \
 111                 printf (fmt ,##args);   \
 112         } while (0)
 113 #else
 114 #define PRINTD(fmt,args...)
 115 #endif
 116
 117 /*-----------------------------------------------------------------------
 118  * Local functions
 119  */
 120 #if !defined(CONFIG_SYS_I2C_INIT_BOARD)
 121 static void  send_reset (void);
 122 #endif
 123 static void  send_start (void);
 124 static void  send_stop  (void);
 125 static void  send_ack   (int);
 126 static int   write_byte (uchar byte);
 127 static uchar read_byte  (int);
 128
 129 #if !defined(CONFIG_SYS_I2C_INIT_BOARD)
 130 /*-----------------------------------------------------------------------
 131  * Send a reset sequence consisting of 9 clocks with the data signal high
 132  * to clock any confused device back into an idle state.  Also send a
 133  * <stop> at the end of the sequence for belts & suspenders.
 134  */
 135 static void send_reset(void)
 136 {
 137         I2C_SOFT_DECLARATIONS   /* intentional without ';' */
 138         int j;
 139
 140         I2C_SCL(1);
 141         I2C_SDA(1);
 142 #ifdef  I2C_INIT
 143         I2C_INIT;
 144 #endif
 145         I2C_TRISTATE;
 146         for(j = 0; j < 9; j++) {
 147                 I2C_SCL(0);
 148                 I2C_DELAY;
 149                 I2C_DELAY;
 150                 I2C_SCL(1);
 151                 I2C_DELAY;
 152                 I2C_DELAY;
 153         }
 154         send_stop();
 155         I2C_TRISTATE;
 156 }
 157 #endif
 158
 159 /*-----------------------------------------------------------------------
 160  * START: High -> Low on SDA while SCL is High
 161  */
 162 static void send_start(void)
 163 {
 164         I2C_SOFT_DECLARATIONS   /* intentional without ';' */
 165
 166         I2C_DELAY;
 167         I2C_SDA(1);
 168         I2C_ACTIVE;
 169         I2C_DELAY;
 170         I2C_SCL(1);
 171         I2C_DELAY;
 172         I2C_SDA(0);
 173         I2C_DELAY;
 174 }
 175
 176 /*-----------------------------------------------------------------------
 177  * STOP: Low -> High on SDA while SCL is High
 178  */
 179 static void send_stop(void)
 180 {
 181         I2C_SOFT_DECLARATIONS   /* intentional without ';' */
 182
 183         I2C_SCL(0);
 184         I2C_DELAY;
 185         I2C_SDA(0);
 186         I2C_ACTIVE;
 187         I2C_DELAY;
 188         I2C_SCL(1);
 189         I2C_DELAY;
 190         I2C_SDA(1);
 191         I2C_DELAY;
 192         I2C_TRISTATE;
 193 }
 194
 195 /*-----------------------------------------------------------------------
 196  * ack should be I2C_ACK or I2C_NOACK
 197  */
 198 static void send_ack(int ack)
 199 {
 200         I2C_SOFT_DECLARATIONS   /* intentional without ';' */
 201
 202         I2C_SCL(0);
 203         I2C_DELAY;
 204         I2C_ACTIVE;
 205         I2C_SDA(ack);
 206         I2C_DELAY;
 207         I2C_SCL(1);
 208         I2C_DELAY;
 209         I2C_DELAY;
 210         I2C_SCL(0);
 211         I2C_DELAY;
 212 }
 213
 214 /*-----------------------------------------------------------------------
 215  * Send 8 bits and look for an acknowledgement.
 216  */
 217 static int write_byte(uchar data)
 218 {
 219         I2C_SOFT_DECLARATIONS   /* intentional without ';' */
 220         int j;
 221         int nack;
 222
 223         I2C_ACTIVE;
 224         for(j = 0; j < 8; j++) {
 225                 I2C_SCL(0);
 226                 I2C_DELAY;
 227                 I2C_SDA(data & 0x80);
 228                 I2C_DELAY;
 229                 I2C_SCL(1);
 230                 I2C_DELAY;
 231                 I2C_DELAY;
 232
 233                 data <<= 1;
 234         }
 235
 236         /*
 237          * Look for an <ACK>(negative logic) and return it.
 238          */
 239         I2C_SCL(0);
 240         I2C_DELAY;
 241         I2C_SDA(1);
 242         I2C_TRISTATE;
 243         I2C_DELAY;
 244         I2C_SCL(1);
 245         I2C_DELAY;
 246         I2C_DELAY;
 247         nack = I2C_READ;
 248         I2C_SCL(0);
 249         I2C_DELAY;
 250         I2C_ACTIVE;
 251
 252         return(nack);   /* not a nack is an ack */
 253 }
 254
 255 /*-----------------------------------------------------------------------
 256  * if ack == I2C_ACK, ACK the byte so can continue reading, else
 257  * send I2C_NOACK to end the read.
 258  */
 259 static uchar read_byte(int ack)
 260 {
 261         I2C_SOFT_DECLARATIONS   /* intentional without ';' */
 262         int  data;
 263         int  j;
 264
 265         /*
 266          * Read 8 bits, MSB first.
 267          */
 268         I2C_TRISTATE;
 269         I2C_SDA(1);
 270         data = 0;
 271         for(j = 0; j < 8; j++) {
 272                 I2C_SCL(0);
 273                 I2C_DELAY;
 274                 I2C_SCL(1);
 275                 I2C_DELAY;
 276                 data <<= 1;
 277                 data |= I2C_READ;
 278                 I2C_DELAY;
 279         }
 280         send_ack(ack);
 281
 282         return(data);
 283 }
 284
 285 /*-----------------------------------------------------------------------
 286  * Initialization
 287  */
 288 static void soft_i2c_init(struct i2c_adapter *adap, int speed, int slaveaddr)
 289 {
 290 #if defined(CONFIG_SYS_I2C_INIT_BOARD)
 291         /* call board specific i2c bus reset routine before accessing the   */
 292         /* environment, which might be in a chip on that bus. For details   */
 293         /* about this problem see doc/I2C_Edge_Conditions.                  */
 294         i2c_init_board();
 295 #else
 296         /*
 297          * WARNING: Do NOT save speed in a static variable: if the
 298          * I2C routines are called before RAM is initialized (to read
 299          * the DIMM SPD, for instance), RAM won't be usable and your
 300          * system will crash.
 301          */
 302         send_reset ();
 303 #endif
 304 }
 305
 306 /*-----------------------------------------------------------------------
 307  * Probe to see if a chip is present.  Also good for checking for the
 308  * completion of EEPROM writes since the chip stops responding until
 309  * the write completes (typically 10mSec).
 310  */
 311 static int soft_i2c_probe(struct i2c_adapter *adap, uint8_t addr)
 312 {
 313         int rc;
 314
 315         /*
 316          * perform 1 byte write transaction with just address byte
 317          * (fake write)
 318          */
 319         send_start();
 320         rc = write_byte ((addr << 1) | 0);
 321         send_stop();
 322
 323         return (rc ? 1 : 0);
 324 }
 325
 326 /*-----------------------------------------------------------------------
 327  * Read bytes
 328  */
 329 static int  soft_i2c_read(struct i2c_adapter *adap, uchar chip, uint addr,
 330                         int alen, uchar *buffer, int len)
 331 {
 332         int shift;
 333         PRINTD("i2c_read: chip %02X addr %02X alen %d buffer %p len %d\n",
 334                 chip, addr, alen, buffer, len);
 335
 336 #ifdef CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW
 337         /*
 338          * EEPROM chips that implement "address overflow" are ones
 339          * like Catalyst 24WC04/08/16 which has 9/10/11 bits of
 340          * address and the extra bits end up in the "chip address"
 341          * bit slots. This makes a 24WC08 (1Kbyte) chip look like
 342          * four 256 byte chips.
 343          *
 344          * Note that we consider the length of the address field to
 345          * still be one byte because the extra address bits are
 346          * hidden in the chip address.
 347          */
 348         chip |= ((addr >> (alen * 8)) & CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW);
 349
 350         PRINTD("i2c_read: fix addr_overflow: chip %02X addr %02X\n",
 351                 chip, addr);
 352 #endif
 353
 354         /*
 355          * Do the addressing portion of a write cycle to set the
 356          * chip's address pointer.  If the address length is zero,
 357          * don't do the normal write cycle to set the address pointer,
 358          * there is no address pointer in this chip.
 359          */
 360         send_start();
 361         if(alen > 0) {
 362                 if(write_byte(chip << 1)) {     /* write cycle */
 363                         send_stop();
 364                         PRINTD("i2c_read, no chip responded %02X\n", chip);
 365                         return(1);
 366                 }
 367                 shift = (alen-1) * 8;
 368                 while(alen-- > 0) {
 369                         if(write_byte(addr >> shift)) {
 370                                 PRINTD("i2c_read, address not <ACK>ed\n");
 371                                 return(1);
 372                         }
 373                         shift -= 8;
 374                 }
 375
 376                 /* Some I2C chips need a stop/start sequence here,
 377                  * other chips don't work with a full stop and need
 378                  * only a start.  Default behaviour is to send the
 379                  * stop/start sequence.
 380                  */
 381 #ifdef CONFIG_SOFT_I2C_READ_REPEATED_START
 382                 send_start();
 383 #else
 384                 send_stop();
 385                 send_start();
 386 #endif
 387         }
 388         /*
 389          * Send the chip address again, this time for a read cycle.
 390          * Then read the data.  On the last byte, we do a NACK instead
 391          * of an ACK(len == 0) to terminate the read.
 392          */
 393         write_byte((chip << 1) | 1);    /* read cycle */
 394         while(len-- > 0) {
 395                 *buffer++ = read_byte(len == 0);
 396         }
 397         send_stop();
 398         return(0);
 399 }
 400
 401 /*-----------------------------------------------------------------------
 402  * Write bytes
 403  */
 404 static int  soft_i2c_write(struct i2c_adapter *adap, uchar chip, uint addr,
 405                         int alen, uchar *buffer, int len)
 406 {
 407         int shift, failures = 0;
 408
 409         PRINTD("i2c_write: chip %02X addr %02X alen %d buffer %p len %d\n",
 410                 chip, addr, alen, buffer, len);
 411
 412         send_start();
 413         if(write_byte(chip << 1)) {     /* write cycle */
 414                 send_stop();
 415                 PRINTD("i2c_write, no chip responded %02X\n", chip);
 416                 return(1);
 417         }
 418         shift = (alen-1) * 8;
 419         while(alen-- > 0) {
 420                 if(write_byte(addr >> shift)) {
 421                         PRINTD("i2c_write, address not <ACK>ed\n");
 422                         return(1);
 423                 }
 424                 shift -= 8;
 425         }
 426
 427         while(len-- > 0) {
 428                 if(write_byte(*buffer++)) {
 429                         failures++;
 430                 }
 431         }
 432         send_stop();
 433         return(failures);
 434 }
 435
 436 /*
 437  * Register soft i2c adapters
 438  */
 439 U_BOOT_I2C_ADAP_COMPLETE(soft00, soft_i2c_init, soft_i2c_probe,
 440                          soft_i2c_read, soft_i2c_write, NULL,
 441                          CONFIG_SYS_I2C_SOFT_SPEED, CONFIG_SYS_I2C_SOFT_SLAVE,
 442                          0)
 443 #if defined(I2C_SOFT_DECLARATIONS2)
 444 U_BOOT_I2C_ADAP_COMPLETE(soft01, soft_i2c_init, soft_i2c_probe,
 445                          soft_i2c_read, soft_i2c_write, NULL,
 446                          CONFIG_SYS_I2C_SOFT_SPEED_2,
 447                          CONFIG_SYS_I2C_SOFT_SLAVE_2,
 448                          1)
 449 #endif
 450 #if defined(I2C_SOFT_DECLARATIONS3)
 451 U_BOOT_I2C_ADAP_COMPLETE(soft02, soft_i2c_init, soft_i2c_probe,
 452                          soft_i2c_read, soft_i2c_write, NULL,
 453                          CONFIG_SYS_I2C_SOFT_SPEED_3,
 454                          CONFIG_SYS_I2C_SOFT_SLAVE_3,
 455                          2)
 456 #endif
 457 #if defined(I2C_SOFT_DECLARATIONS4)
 458 U_BOOT_I2C_ADAP_COMPLETE(soft03, soft_i2c_init, soft_i2c_probe,
 459                          soft_i2c_read, soft_i2c_write, NULL,
 460                          CONFIG_SYS_I2C_SOFT_SPEED_4,
 461                          CONFIG_SYS_I2C_SOFT_SLAVE_4,
 462                          3)
 463 #endif
 464 #if defined(I2C_SOFT_DECLARATIONS5)
 465 U_BOOT_I2C_ADAP_COMPLETE(soft04, soft_i2c_init, soft_i2c_probe,
 466                          soft_i2c_read, soft_i2c_write, NULL,
 467                          CONFIG_SYS_I2C_SOFT_SPEED_5,
 468                          CONFIG_SYS_I2C_SOFT_SLAVE_5,
 469                          4)
 470 #endif
 471 #if defined(I2C_SOFT_DECLARATIONS6)
 472 U_BOOT_I2C_ADAP_COMPLETE(soft05, soft_i2c_init, soft_i2c_probe,
 473                          soft_i2c_read, soft_i2c_write, NULL,
 474                          CONFIG_SYS_I2C_SOFT_SPEED_6,
 475                          CONFIG_SYS_I2C_SOFT_SLAVE_6,
 476                          5)
 477 #endif
 478 #if defined(I2C_SOFT_DECLARATIONS7)
 479 U_BOOT_I2C_ADAP_COMPLETE(soft06, soft_i2c_init, soft_i2c_probe,
 480                          soft_i2c_read, soft_i2c_write, NULL,
 481                          CONFIG_SYS_I2C_SOFT_SPEED_7,
 482                          CONFIG_SYS_I2C_SOFT_SLAVE_7,
 483                          6)
 484 #endif
 485 #if defined(I2C_SOFT_DECLARATIONS8)
 486 U_BOOT_I2C_ADAP_COMPLETE(soft07, soft_i2c_init, soft_i2c_probe,
 487                          soft_i2c_read, soft_i2c_write, NULL,
 488                          CONFIG_SYS_I2C_SOFT_SPEED_8,
 489                          CONFIG_SYS_I2C_SOFT_SLAVE_8,
 490                          7)
 491 #endif
 492 #if defined(I2C_SOFT_DECLARATIONS9)
 493 U_BOOT_I2C_ADAP_COMPLETE(soft08, soft_i2c_init, soft_i2c_probe,
 494                          soft_i2c_read, soft_i2c_write, NULL,
 495                          CONFIG_SYS_I2C_SOFT_SPEED_9,
 496                          CONFIG_SYS_I2C_SOFT_SLAVE_9,
 497                          8)
 498 #endif
 499 #if defined(I2C_SOFT_DECLARATIONS10)
 500 U_BOOT_I2C_ADAP_COMPLETE(soft09, soft_i2c_init, soft_i2c_probe,
 501                          soft_i2c_read, soft_i2c_write, NULL,
 502                          CONFIG_SYS_I2C_SOFT_SPEED_10,
 503                          CONFIG_SYS_I2C_SOFT_SLAVE_10,
 504                          9)
 505 #endif
 506 #if defined(I2C_SOFT_DECLARATIONS11)
 507 U_BOOT_I2C_ADAP_COMPLETE(soft10, soft_i2c_init, soft_i2c_probe,
 508                          soft_i2c_read, soft_i2c_write, NULL,
 509                          CONFIG_SYS_I2C_SOFT_SPEED_11,
 510                          CONFIG_SYS_I2C_SOFT_SLAVE_11,
 511                          10)
 512 #endif
 513 #if defined(I2C_SOFT_DECLARATIONS12)
 514 U_BOOT_I2C_ADAP_COMPLETE(soft11, soft_i2c_init, soft_i2c_probe,
 515                          soft_i2c_read, soft_i2c_write, NULL,
 516                          CONFIG_SYS_I2C_SOFT_SPEED_12,
 517                          CONFIG_SYS_I2C_SOFT_SLAVE_12,
 518                          11)
 519 #endif